Garden sauna foundations: block paving or a concrete slab?
A timber-frame sauna weighs 1.9–2.5 tonnes and arrives in one piece. The foundation must carry that load evenly and stay level for years. We compare the two most common solutions.
Concrete slab: certainty for decades
A 15 cm slab, mesh-reinforced and laid on 20 cm of compacted sub-base, is the maintenance-free option. It spreads the load evenly, does not settle locally, and lets you route conduits precisely for the 400 V heater supply and water drainage.
The slab should exceed the sauna footprint by 10 cm on every side. For the Vetta with vestibule that means a 520 × 260 cm slab – the exact dimensions are in the PDF floor plan on the product page.
Block paving: faster and cheaper, with conditions
Paving can carry a sauna if the sub-base is done properly: at least 25 cm of compacted crushed aggregate (0–31.5 mm), compacted in 10 cm layers, with a fall of at most 0.5%. Paving laid directly on sand will settle unevenly under 2 tonnes.
Before delivery we check levelness with a 4 m straightedge – the tolerance is ±5 mm. If the surface already exists, send us photos via the configurator form and our technician will assess it before transport.
Drainage and floor ventilation
Whatever the surface, the sauna stands on thermowood bearers that create a 5 cm ventilation gap. Water from the bucket and melting snow need somewhere to go – avoid siting the sauna in a dip and plan a fall away from the building.
Remember access too: the crane truck needs 3.5 m of width and lifts the sauna up to 8 m. You can read more about a typical delivery day on the saunas with vestibule page.
TIKKA recommendation
Building from scratch? Choose the concrete slab – the cost difference versus a proper paving sub-base is small, and you get a maintenance-free foundation with conduits in the right places. We provide the foundation plan with connection points after ordering.